Subaru fan not turning on.

[simple_gifts]

My friend's son has a late 90's subaru which is overheating. I don't have access to the car, but it seems there are (2) coolant temperature sensors; one for the dash gauge and one for the ECU. Does the ECU one also control the fan?

I see this

http://www.rockauto.com/catalog/moreinfo.php?pk=4664736&cc=1269053&jnid=440&jpid=0

But that seems to be a generic fan control that fits millions of cars. Should I be assuming that a simple thermometer type device controls the fan turning on and off?

The car is a mutant; it is an 1997 Impreza hatch with a 2.5L block that has been rebuilt. I will also be buying a thermostat and getting that replaced.

Would appreciate any 'subaru specfic' idiosyncrasies if applicable

Thanks.

 

[jc1112]

I had a 2003 wrx and after a new radiator with aftermarket fans, the fans would not turn on and the car overheated once.

long story short the fuses were blowing because of improper wiring. the web forum
known as nasioc had the answer as what wires were placed where...

...check cheap simple stuff first and go from there is my advice and i believe the ecu controls the fans.

 

[Wheel]

Make sure it has a Subaru thermostat. It is sized differently than almost all aftermarket ones. Subaru's is much larger. Check the lines to the heater core, hard and flex, as well as the heater core. The ecu sensor runs the fan. Like JC1112 says, nasioc is a good resource.

If it's a 97 quad cam 2.5, they were prone to internal head gasket leaks. The combustion pressure would blow into the cooling system, it would push it all out thru the overflow tank. You can get a exhaust gas tester to test the coolant, but give the other stuff a try first.

 

[Chris142]

If you jump the fans from the battery do they work?

 

[Donald]

A bidirectional OBDII code reader can turn on the fan via command. Probably only a shop would have this type of OBDII code reader.

 

[eljefino]

If it has AC that should force the fans on.

If you see a "single pin" connector in the t-stat housing that typically runs the gauge or fan switch, though 97 should have that stuff run by the computer, though the Japanese are conservative on that sort of thing. Check its resistance to ground: infinite is fan off, zero fan on, something in the middle is a value for a gauge.

That Rockauto fan control would take over from the PCM controlled one but could throw a code for the PCM not being in control.